I’d seen this somewhere before, but thought I’d benchmark it to see if it was true. Ruby has 3 classes for doing dates. There is Date, DateTime and Time classes. In languages like C# and PHP, the equivalent DateTime class is the one that is generally utilized to do date/time manipulations. However, in Ruby, DateTime and Time are nearly identical classes, the difference being that DateTime is a convenience class. Benchmarking shows the DateTime class to be 20-25 times slower than the native Time class. After doing a little research, the reason is clear. The Time class is a native class developed in C, the DateTime is a wrapper class written in Ruby. So while I rarely have occasion to do time manipulation in a loop — it would seem that the DateTime class should pretty much always be avoided. In fact, I can’t see why the DateTime class exists. I don’t see what it does that isn’t available in either the Date class or Time class.